<!DOCTYPE html>
<html class="reftest-wait">
<title>Tests anchor positioning with nested scroll containers</title>
<link rel="author" href="mailto:xiaochengh@chromium.org">
<link rel="help" href="https://drafts.csswg.org/css-anchor-1/">
<link rel="match" href="reference/anchor-scroll-nested-ref.html">
<style>
body {
  margin: 0;
  width: 1500px;
  height: 1500px;
  position: relative;
}

#outer-scroller {
  margin: 500px;
  width: 350px;
  height: 350px;
  outline: 1px solid black;
  overflow: scroll;
}

#inner-scroller {
  margin: 100px;
  width: 250px;
  height: 250px;
  outline: 1px solid black;
  overflow: scroll;
}

#anchor {
  margin: 200px;
  width: 50px;
  height: 50px;
  background-color: green;
  anchor-name: --anchor;
}

.anchored {
  position: absolute;
  width: 50px;
  height: 50px;
  left: anchor(left);
  position-anchor: --anchor;
}

.above {
  bottom: anchor(top);
  background-color: red;
}

.below {
  top: anchor(bottom);
  background-color: yellow;
}
</style>

<div id="outer-scroller">
  <div id="inner-scroller">
    <div id="anchor"></div>
    <div class="anchored above"></div>
  </div>
</div>

<div class="anchored below"></div>

<script>
function raf() {
  return new Promise(resolve => requestAnimationFrame(resolve));
}

async function runTest() {
  await raf();
  await raf();

  document.documentElement.scrollTop = 400;
  document.documentElement.scrollLeft = 400;

  let outerScroller = document.getElementById('outer-scroller');
  outerScroller.scrollTop = 50;
  outerScroller.scrollLeft = 50;

  let innerScroller = document.getElementById('inner-scroller');
  innerScroller.scrollTop = 100;
  innerScroller.scrollLeft = 100;

  document.documentElement.classList.remove('reftest-wait');
}
runTest();
</script>
